Ruus, who competes for Åsarna IK , became Swedish Junior Champion over 10 km classic in Boden in March 2011 and competed internationally for the first time at the 2012 Winter Youth Olympic Games in Innsbruck . There he was tenth over 10 km classic, sixth with the mixed relay and fourth in the sprint. At the Nordic Junior World Ski Championships in 2012 in Erzurum , he finished 67th over 10 km classic. The following year he won the bronze medal with the relay at the Nordic Junior World Ski Championships in Liberec . He also achieved 23rd place in the skiathlon there . He ran his first race in the Scandinavian Cup in January 2013 in Östersund , which he finished in 137th place over 15 km freestyle and 106th place in the sprint. At the Nordic Junior World Ski Championships in 2014 in Val di Fiemme he came in 12th place in the skiathlon, on the sixth place over 10 km classic and on the fourth place with the relay and at the U23 World Championships in 2015 in Almaty on the 24th place. Place in sprint and 11th place in skiathlon and 15 km freestyle. He made his World Cup debut in February 2015 in Östersund, where he finished 79th in the 15 km freestyle. At the U23 World Championships in 2016 in Râșnov , he achieved 37th place over 15 km classic and 36th place over 15 km freestyle and at the U23 World Championships 2017 in Soldier Hollow he came 39th over 5 km freestyle and 22nd place in the sprint. In February 2020, he took 28th place in the 15 km mass start race in Falun, earning his first World Cup points. In the subsequent ski tour, which he finished in 28th place, he came back into the points.
Sweden
